Fail-safe subsea fluid transportation system



FAIL-SAFE SUBSEA FLUID TRANSPORTATION SYSTEM Filed June 29. 1967 W. B.BROOKS July 8, 1969 Sheet INVENTOR WARREN B. BROOKS ATTORNEY I July-8,1969 w, BROOKS 3,454,083

FAIL-SAFE SUBSEA FLUID TRANSPORTATION SYSTEM Filed June 29, 1967 v Sheet3 of s FIG. IA

INVENTOR WARREN B.v BROOKS ATTORNEY July 8, 1969 w. B. BROOKS 3,454,033

I FAIL-SAFE SUBSEA FLUID TRANSPORTATION SYSTEM Filed June 29. 1967 I I ISheet 3 of s INVEN'l OR WARREN B. BROOKS %& PM/

ATTORNE! United States Patent US. Cl. 166-5 6 Claims ABSTRACT OF THEDISCLOSURE This specification discloses a subsea system for theproduction of fluid minerals. The system includes a product gatheringnetwork provided with production satellites in which the gas-oil-Waterratios of each well are periodically tested and the flow rates areautomatically controlled. A power distribution network connects acentral power station, either floating or bottom supported, at the siteor on land nearby, with the various satellite stations and submergedwellhead units. Provision is made for entry into the satellites anddiver maintenance at the submerged wellheads. A rigid transportationpipe transports produced fluids to the water surface. At the lower endof the rigid transportation pipe is a designed break-away section whichwill be broken if excessive strain is encountered. An inverted funnel islocated over the break-away section to trap any escaping fluid.

BACKGROUND OF THE INVENTION Field of the invention This inventionrelates to a subsea system for the recovery of subaqueous deposits offluid minerals. By the term fluid is meant any slurry or other state ofmatter which will pass through a conduit or pipe. More particularly, theinvention relates to the production of gas and/or oil from subaqueousformations utilizing a systern of submerged wellheads and a productgathering network in combination with submersible automated and/ orsemiautomated equipment.

Description of the prior art Present developments in the offshore oiland gas industry indicate that production efforts will be extended, inthe near future, to undersea areas, such as the outer fringes of thecontinental shelves and the continental slopes, where a submarineproduction system is believed to be the most practical method ofreaching the subaqueous deposits. Although hydrocarbons are the mainconcern at this time, it is contemplated that subaqueous deposits ofsulfur and other minerals will be produced from beneath the seas in avery few years. While bottom-supported permanent surface installationshave proved to be economically and technologically feasible incomparatively shallow waters, it is believed that in the deeper watersof the continental shelves (over three hundred feet) and the continentalslopes (depths oversix hundred feet), the utilization of such surfaceinstallations must be limited to very special situations. Installationsextending above the water surface are also disadvantageous even inshallower water where there are adverse surface conditions, such as inthe Arctic areas where the bottomsupported structure of above-surfaceproduction platforms are subject to ice loading. The tides, which mayrun up to thirty feet in the northern latitudes, such as in Cook Inlet,Alaska, tend to lift the ice formed on the legs of the platform and tearthe anchoring means therefor completely out of the sea bottom as well asdriving brokenup sheet ice laterally against the platforms at six toeight knots or more. In some areas commercial shipping and 3,454,083Patented July 8, 1969 pleasure boats present a constant source of dangerto above-surface installations, while recreation and area beautificationmay provide man-made obstacles to their erection, particularly nearseaside resort areas and seaport cities.

The sheltering of production equipment beneath the surface of the sea,while believed to be economically feasible at depths of over threehundred feet, even where adverse conditions are not present, stillpresents many technical problems, particularly with respect to theservicing and maintenance thereof. With a deep water subsea system, themajority of the maintenance and servicing problems encountered must behandled automatically, or at least by remote control, due to the costand limitations on deep diving at the present time; however, thereshould be provisions for having divers at the scene of installed subseaequipment in the event that the necessary manipulations are toocomplicated for anything but direct human control. The use ofsubmersible vehicles, with articulated manipulators, for performing avariety of subsea operations has been generally proven and such vehiclescan fill much of the gap between completely automated equipment andoperations that must be performed by divers.

SUMMARY OF THE INVENTION The present invention provides a fail-safesystem for transporting fluid minerals underlying a body of water to asurface station. The system includes a rigid fluid trans- :portationpipe which extends from the water surface and terminates in an invertedfunnel near the water bottom. A conduit connected to a source ofproduced fluids is adapted to direct the fluids into the lower end ofthe rigid pipe. A portion of the conduit means within the invertedfunnel includes a designed break-away section which will be broken ifexcessive strain is encountered. The inverted .funnel will trap anescaping fluid and thus fluid lost will be kept to a minimum.

The present invention may be included in a subsea production systemincluding satellite gathering stations for testing the produced eflluentfrom submerged wellheads of spaced subaqueous wells whose products aredirected therethrough, and in response, controlling the wellhead valvesof the respective subaqueous wells. While the satellite stations aredesigned for automatic and/or remote operation, there are provided meansfor the safe entry of personnel for maintenance and repair. Furthermore,the satellite stations are each constructed so as to prevent perniciousvapors leaking from the production equipment from contaminating the lifesupport sections of a satellite station.

BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is a pictorial representationof a portion of a subsea producing system in accordance with thisinvention;

FIGURE 1A is an elevational View, partially in schematic and partiallyin cross section, of a system for transporting the produced fluids froma subsea satellite pumping station to a floating storage tank; and

FIGURE 2 is an elevational view, partially broken away, of a subseasatellite station forming a portion of the subsea producing system ofthe present invention.

DESCRIPTION OF SPECIFIC EMBODIMENTS Now referring to FIGURE 1, there isshown a subsea production system in operation in the background and acontinuation of the flowlines therefrom being installed on the oceanbottom in the foreground. Submerged production oil and/or gas wellheadunits, generally designated 10, on the marine bottom 12 are connectedinto the subsea system through satellite stations, generally designated14 and 16, by means of flowlines 18. The satellite station 14 functionsas a production gathering point, information center, and automaticcontrol center for its associated wells, while the satellite station 16provides all of the functions of the station 14 while also having addedpumping facilities for forcing the produced hydrocarbons up to afloating storage tank 20. The stored hydrocarbons are removed from thefloating storage tank 20 by a tanker 22, floating on the water surface24, which visits the storage tank 20 and is moored thereto at prescribedintervals. As shown, the tanker 22 is located with respect to thestorage tank by mooring lines 21 while onloading through a floating hose23 connected to an outlet of the storage tank 20. A floating centralcontrol and power generating station 26 is moored above the subaqueousproducing field by lines 27 and is connected to the satellite 14 by abundle of electrical lines 28,for information input and retrieval,command signals, and the supplying of electrical power to the subseasystem. It is contemplated that personnel would live on the station 26to supervise continuously the operation of the subsea production system.Electric power is distributed, along the marine bottom 12, to thevarious wellhead units shown, the satellite station 16, and othersatellite stations 14 from the illustrated satellite station 14.

Although the central control and power generating station 26 isillustrated as floating on the surface of the body of water just abovethe subsea production system, depending upon the distance from shore,the floating station 26 could be dispensed with entirely and theelectrical power lines as well as the information input and retrieveland command signal lines could be laid across the ocean bottom to anonshore station. Another possibility is that the floating station 26,while having the equipment for generating power built thereon, would bemerely a link between the submerged satellite 14 and a station ashorefor the transmission of information to and from shore and commandsignals to the satellite through the illustrated antenna 30. A microwaverelay system, of the type now utilized in conjunction with sameplatform-produced fields in the Gulf of Mexico, would be acceptable forthis purpose.

Various valves and controls situated at the wellhead units 10 wouldnormally be controlled by interconnecting hydraulic or electrical linesfrom within the satellites 14 and 16. However, if there should be abreakdown in communication between a wellhead unit 10 and its respectivecontrolling satellite 14 or 16, articulated armed robot submersiblevehicles, generally designated 32 (the nearer one shown handling pipe),remotely controlled from surface vessels 34, would be utilized. Suchvehicles, directed by the aid of remote viewers such as televisioncameras 36 in clear water, or sonic or laser viewers in murky water,mounted thereon, would be much less expensive than a manned vehicle withits attendant life support systems. However, in instances where directobservation is necessary, submersible vehicles having articulatedmanipulators, such as the illustrated submersible vehicles, generallydesignated 38, are useful; the vehicle 38 at the right is observing apipe-laying operation, while the vehicle 38 at the left is about tooperate a flowline valve 40 by the use of a rotary actuator tool 42adapted to fit an upwardly extending nut 44 forming the valve actuator.A tool, such as the rotary actuator tool 42, as well as a number ofother tools to be used in conjunction with the articulated manipulatorsof submersible vehicles are pictured on pp. 653-661 of the book,Proceedings of OECON-Offshore Exploration Conference, 1966, published byM. J. Richardson Inc., 2516 Via Tejon, Palos Verdes Estates, Calif. Theother articulated manipulator terminates in a plate like tool 46 used asa reaction member to prevent the vehicle 38 from turning rather than thevalve actuator nut 44. The valve 40 would normally be controlled from asatellite station 14, 16 through the control line 48 strapped thereto.Along the outer shell of the submersible vehicles 38 are pockets orhooks (not shown) for carrying as many different tools as may benecessary. By using one of the many known quick release couplings, anarticulated manipulator can easily be released from a first toolconnected to the outer end thereof and to a second tool fixed thereon.As will be explained later, a similar manned submersible vehicle canalso be utilized as a rest station for divers working at a nearbywellhead unit 10 or other equipment.

Individual wellhead units 10, as well as the satellite stations 14 and16, can be installed at the proposed location without the need fordivers. It is now well within the skill of the art to remotely locateequipment on the marine bottom 12, in the proper orientation, and secureit in place. One of the major problems remaining, however, is that ofconnecting the individual production units of the subsea systemtogether. As shown in the foreground of FIGURE 1, sections of pipe 50 ofa flowline 18, to be connected between the illustrated satellite 14 anda wellhead unit 10 off to the right of the drawing in the foreground,are being installed on a shelf '51 of the marine bottom 12 by the use ofone of the unmanned remotely controlled articulated submersible vehicles32 and a robot welder, generally designated 52.

The robot welder 52 comprises a tanklike body 54 supported above thepath of the flowline 18', being installed, on a pair of opposed endlesstreads 56 driven by a motor and transmission means (not shown) withinthe tank 54. The robot welder 52 would normally be supported on themarine bottom 12 by the treads 56, but in areas where bottom sedimentswould not support the weight of the robot welder 52, buoyancy chamberswould be built into the tanklike body 54.

Extending out ahead of the tank 54 is a welding ring 58 which encirclesthe flowline 18' and is held in a vertical position by a strut 60extending out from the front of the tanklike body 54. A welding head 62is contained on a track (not shown) around the inside face of thewelding ring 58 so that a welding bead is formed which completelyencircles a joint 63 between abutting sections of pipe 50. The weldingring 58 is formed of a pair of semicircular members pivoted about thepoint of connection with the strut 60. A hydraulic piston cylinder 61,connected between a point on each semicircular member of the weldingring 58 and the pivot point to control the opening and closing of thewelding ring 58. The ability of the welding ring to open permits therobot welder to mount a flowline 18 intermediate the ends thereof. Apair of aligned pipe clamps 64 and 66 hold the abutting ends of adjacentsections of pipe 50 together and in alignment prior to and during thewelding operation. The pipe gripping portion of clamp 64 and a pair ofsemicircular jaws 68 are actuated by extensible struts having hydraulicpiston-cylinder arrangements '63 connected between each of the jaws 68and an outwardly extending anchoring arm 70 from which the jaws 68pivot. The jaws of the clamp '66 are pivoted from the underside of thestrut under the control of extensible struts 65. With the jaws of theclamps 64 and 66 reopening, the robot welder 52 can move up the flowline18' to the next point at which a weld is needed. The closing of theclamp 66 aligns the end of the last pipe section 50 of the flowline 18'and the welding ring 58. The still opened jaws 68 of the clamp 64 permitthe remotely controlled submersible vehicle 32 (in the right foreground)to slide a new pipe section 50 into the jaws 68 of the clamp 64 by meansof the hand or vice-type extension tools 72 at the ends of itsarticulated manipulators 74. A pile 86 of pipe sections is stacked onthe shelf 51 just behind the flowline 18' being fabricated. When theremotely controlled submersible vehicle 32 delivers a pipe section 50,that it is carrying, to the robot welder 52, it is sent back to pick upanother pipe section 50 from the pile 86. The vessel 34 from which theremotely controlled submersible vehicle 32 and welder 52 are bothcontrolled has a crane 88 capable of lowering further stacks 90 of pipesections 50 down to the flowline 18' being fabricated.

In connecting two of the subsea producing units with a flowline, it isadvantageous to use a collet connector (not shown) at each fixed unitsince the robot welder 52 is not suited to forming any but abuttingwelds between pipe sections of substantially equal diameters. To startthe flowline, a first pipe section is transported by the submersiblevehicle 32 to the fixed producing unit from which the flowline is to bestarted. The end of a pipe section is inserted into a collet connectorforming the outer portion of a port in the unit. The collet connector isactuated to lock the pipe section in place from a central facility, or asurface vessel, or from the submersible vehicle. The robot welder 52 isthen lowered onto the pipe section 50', forming the beginning of aflowline with both sets of pipe clamps 64 and 6-6 as well as the weldingring 58 held open. When the welder 52 has settled down on the unfinishedflowline, the welding ring 58 may be closed and is not again openeduntil the flowline is completed. Sections of pipe are added to theflowline and welded in place as discussed above. As the flowline reachesa point at which it is only one pipe section or less from the secondproducing unit, a measured pipe section is brought up which will lock ina collet connector terminating a port in the second unit while abuttingthe last pipe section of the unfinished flowline. The last joint is thenwelded between the measured pipe section and the unfinished flowlineafter which the clamps 64 and 66 as well as the welding ring 58 are allopened permitting the robot welder 52 to be lifted off of the pipeline18'. At this time the collet connector on the second producing unit isactuated to complete the flowline.

Once the pipe section 50' has been inserted into the enlarged openingthrough the clamp -64 and the new section of pipe 50' abuts tightlyagainst the last welded-on section 50, the jaws 68 of the clamp 64 areclosed, aligning the pipe sections 50 and 50' in abutting relationship.The traveling welding head 62 is then driven around the track within thering 58 to form a circumferential head around the joint after which bothof the clamps 64, 66 are opened. The robot welder '52 then moves on upthe flowline to the new outer end of the flowline 18', one pipe section50 away, and the sequence of operations is repeated. Since the pipesections '50 tend to sink into the mud on the marine bottom '62, a meansmust be pro-. vided for forming a temporary path under the flowline 18'so as not to hinder the movement of the clamps 64, 66 and the ring 58 asthe welder 52 moves forward. A shallow trench is formed ahead of therobot welder 52 by a jet pipe 76 extending out parallel to the flowline18. The tip 78 of the jet pipe 76 is aimed to project fluid underpressure transversely toward, and down slightly below, the flowline 18'.The preferred method is to provide a pump (not shown) with the body 54to pick up sea water through an intake port and drive the water outthrough the jet pipe 76. A television camera 80 (or any other type ofremote viewer as previously discussed) is mounted on top and at thefront of the tanklike body 54 of the robot welder 52 so that the weldingoperations can be observed from the ship 34 (at the left-hand side ofthe drawing) at the surface. The ship 34 and the robot welder 52 areconnected by a hoisting line 82, and a control cable 84 through whichthe television signals are sent to the ship 34 and commands aretransmitted to the welder 52 from the ship. Within the tanklike body 54is the various equipment for directly controlling the movement of therobot welder 52.

Now looking to FIGURE 2, the satellite station 14 has a hollow shell 92comprising a cylindrical center section closed by hemispherical endsections and is divided interiorly into three airtight chambers. Acentral access chamber, generally designated 94, provides an entranceinto the satellite station 14 from one of the submersible vehicles 38from above, or by a diver, through a lock 96 below. The access chamber94 is cylindrical in shape and is divided vertically, by an intermediatelock 98, into an upper compartment through which personnel move betweenthe interior of the satellite station 14 and the submersible vehicle 38and a lower compartment 102 through which a diver 103 enters and leavesthe satellite station '14. Since the satellite station 14 would normallybe maintained at atmospheric pressure, scalable hatches 104 and 107 arenecessary at the lower and intermediate locks 96 and 98, respectively.An upper lock 105 is also sealed (by a nonillustrated hatch) when nosubmersible vehicle 38 is engaged thereto by a depending intermediateaccess tube 106. The submersible vehicle 38 also operates at atmosphericpressure normally, but an internal compartment therein, connected by theaccess tube 106 to the upper lock 105 of the satellite station 14, aswell as the entire central access chamber 94, can be pressured up toaccommodate divers who have worked in the open sea and requiredecompression. The divers in the pressurized compartment in thesubmersible vehicle 38 are transported to a surface ship where there areproper facilities for safe decompression.

All of the hydrocarbon products being produced through the satellitestation 14 are confined to a processing chamber 108, at one end of thesatellite shell 92, walled off by a bulkhead 110, to preventcontamination of the atmosphere in the remainder satellite station 14 ifthere,

should be a leak in the processing equipment. The air purificationequipment 112, pumping equipment 114, and electrical power facilities116 are in separate sealed compartments 118 to 122, respectively, of acontrol chamber 124 at the other end of the satellite station 14 fromthe hydrocarbon processing equipment. An operator 126, shown sitting atacontrol console 128 in the control chamber 124, can monitor and directthe equipment in the hydrocarbon chamber 108 as well as actuating valuesat the wellhead units 10 and fiowlines 18.

Both the upper and lower compartments 100, 102 of the access chamber 94are normally closed to the sea and are held at atmospheric pressure.After the access tube 106, depending from under the submersible vehicle38, makes contact with the lock 105 on the upper end of the satellitestation 14, the two are sealably connected and any water in the accesstube 106 is pumped out by equipment on the submersible vehicle 38. Withan equalization of pressure, the hatch in the lock 105 is opened.Personnel can then enter the upper compartment 100 of the satellitestation 14 directly from the submersible vehicle 38, through the accesstube 106 at atmospheric conditions. Personnel from the submersiblevehicle 38 come down rungs 130, fastened to the interior wall of theaccess chamber 94 to form a ladder, and enter the control chamber 124through a safety airlock 131 and a ladder 133.

If the services of a diver are necessary, scuba or hard hat divingequipment, stored in the chamber 124, are utilized. Once the divingequipment is donned, the diver 103 enters the lower compartment 102,through a safety airlock 132, reseals the safety airlock 132 and makessure the intermediate lock 142 is sealed, and then floods the lowercompartment 102. As the lower compartment 102 fills with water, thediver 103 opens the lower lock 96 and descends into the water. If thejob to be performed takes an extended time at depths of more thanseveral hundred feet, the diver 103 may be limited to as short a workingtime as one-half hour before he must come back to the satellite station14 to rest. In such a case, more than one diver 103 could be used, theremaining members of the working team resting in the atmosphericportions of the satellite station 14 while one of the team works in thewater and each one exiting in turn through the lower lock 96 when thelast one returns to the satellite station. In such a manner, work cancontinue over long periods of time although any one diver 103 cannotstay very long in the hostile environment.

When performing maintenance or inspection work in the processing chamber108, the possibility of a gas leak in the equipment is checked by aworkman donning life support gear such as scuba apparatus entering thechamber 108 with a hand-carried device for detecting toxic, perniciousgases that might be leaking from the processing equipment.Alternatively, a leak detector is mounted in the bulkhead 110 to samplethe atmosphere within the compartment 108 while providing a visualindication to one either within the access chamber 94 or the controlchamber 124. If possible the leak is stopped by shutting off theprocessing equipment from within the control chamber 124. The processingchamber 108 is then flooded while exhausting the contaminated atmosphereto the surrounding water. After re-establishing atmospheric conditionsin the processing chamber 108, the atmosphere within the processingchamber is again checked, and if it is safe a workman can enter to makerepairs. If the leak cannot be stopped in this manner, it will benecessary for a workman, wearing life support gear, to enter thecontaminated processing chamber 108 to manually stop the leak. In theevent that gas is escaping into the processing chamber 108 at a highpressure, too high a pressure for a man to exhaust through his breathingequipment into the processing chamber 108, an exhaust tube (not shown)would be connected from the life support gear back into the controlchamber 124.

It is important to contain the contaminated atmosphere in the processingand access chambers 108, 94. By sealing the safety airlock 132 and theintermediate lock 98 from within the access chamber 94 before opening asafety lock 134, interconnecting the access chamber 94 within theprocessing chamber 108, the noxious fumes can be contained in the lowercompartment 102 of the access chamber 94 and the processing chamber 108.After the maintenance or repair work is completed, the contaminatedatmosphere within the processing chamber 108 and the access chamber 94can be purged, by several alternate procedures. One way is to let inwater under full pressure to displace the contaminated air through aline 136 by a hand-actuated control valve 138 in the lower compartment102. The contaminated air in the lower compartment 102 of the accesschamber 94 and the processing chamber 108 would then be forced outthrough a line 140 controlled by hand-actuated valve 142 also in thelower compartment 102. After the compartment 102 and the processingchamber 108 have been purged of the contaminated atmosphere therein bysea water, the valve 142 is closed and the sea water is pumped outthrough line 136 while air under atmospheric pressure is introduced. Thewater can also be expelled, through the line 136 without directlypumping it out by fresh air that is pumped in under pressure from thecontrol chamber 124. Once all of the water has been expelled and the airpressure in the lower compartment 102 is brought back to atmospheric,the safety airlock 132 is reopened to allow the workmen to re-enter thecontrol chamber 124. There would normally be no decompression problemsassociated with forcing out the contaminated air with ambient pressuresea water as long as the high pressure was not held for more than a fewminutes.

Whenever a man is exposed to high pressures, even for a short time,there is some risk. So, for maximum safety, it is preferred that thecontaminated air be evacuated into the surrounding water through theline 140 with the help of a pump (not shown) in the line. The waterwould be again brought in through the line 136. A pressure regulator(not shown) should be included in the line 136 to prevent the waterpressure inside the satellite shell 92 from rising much aboveatmospheric. After all of the contaminated atmosphere has beendisplaced, the water is pumped out as described above while air underatmospheric pressure is reintroduced. At this time the equipment isrechecked for leaks.

In the instance where there was a very high pressure leak into thechamber 108, it would be dangerous for a man even to enter the chamber108 with any portion of his body uncovered since the contaminatedatmosphere therein could dissolve human skin. In fact, a gas such asmethane would pass right through flesh, into the body fluids, alteringthe body chemistry and killing the man exposed to these conditions.Workmen would either have to wear completely protective clothing or thechamber 108 would have to be flooded prior to being entered and theworkman would then preferably work in the chamber 108 under water. Veryfew materials possess the ability to withstand the onslaught of the highpressure gas and yet have the flexibility necessary for a protectivegarment. If the leak can be remotely stopped the diver would work underwater at atmospheric pressure. If it is not possible to stop the leakprior to the workman entering the processing chamber 108 thediver-workman must work at ambient water pressure.

If the diver-workman must work for a considerable time at ambientpressure, he must be transported to a decompression chamber on anattending surface vessel (not shown) after the repairs are completed.After the repairs are completed in the flooded processing chamber 108,the workman enters the compartment 102, seals the safety lock 134, andhas the water therein pumped out. A breathable atmosphere is pumped intothe compartment 102 at ambient pressure. This can be done easily byopening the valve 138, or the port 96, while pumping high pressure airinto the lower compartment 102 to drive the water out. The uppercompartment is also pressurized. When all the water is evacuated fromthe lower compartment 102, the valve 138 or port 96, whichever wasopened, is closed and the intermediate lock 98 is opened. The workmancan now enter the pressurized compartment in the submersible vehicle 38for transportation to the decompression chamber on the surface vesselwithout passing through an area of low pressure. Before a secondrepairman can enter the processing chamber 108 to check on the repairwork, the pressure in the upper and lower compartments 100, 102 must bepumped down to atmospheric while the water in the chamber 108 is pumpedout and replaced with air at atmospheric pressure so that leaks can bechecked for at atmospheric conditions.

The flowlines 18, extending into the satellite station 14 at the end atwhich the processing chamber 108 is locat ed, are each operativelyconnected by two-position threeway valves 144 to either a group manifold146 or a test manifold 148. In turn, each one of the flowlines 18 isseparately connected to the test manifold 148 while the remainder areconnected to the group manifold 146. From the group manifold 146 theefiluent, flowing through all but one of the lines 18, is conducted,through a main conduit 150, to a main outlet line 152 which in turndepends through the shell 92 of the satellite station 14 and extendsacross the marine bottom 12 to the pumping station in the satellitestation 14 and therethrough to the floating storage tank 20. Theeflluent, from a single flowline 18 at a time, is directed into the testmanifold 148 and therethrough into a. test separator 154, through aninlet line 156. The separated-out gas leaves the separator 154 throughan outlet line 158 and is injected back into the main eflluent stream atthe main outlet line 152. A meter 160 in the gas outlet line 158provides a means for indicating the amount of gas flowing through theline 158. Also in the outlet line 158 is a manual shut-off valve 162 andan automatic valve 164 which is controlled by equipment from within thecontrol chamber 124 of the satellite station 14 for increasing ordecreasing the back pressure on the separator 154. An oil outlet line166 also extends from the test separator 154 to the main outlet line152. The oil outlet line 166 also has a meter 168, a manual shut-offvalve 170, and an automatic valve 172. A dump line 174 is eitherconnected directly between the sump of the separator 154 and the waterout- 9 side the satellite station 14, for ridding the effluent of waterseparated out in the separator 154, or if the pressure in the separatoris too low this waste liquid may have to be pumped out. Line 174 alsoincludes a meter 176, a manual shut-ofl valve 178, and an automaticvalve 180. An automatic satellite gathering and test system, of the typediscussed above, has been explained in detail in the A. E. Barroll etal. Patent No. 3,095,889, issued July 2, 1963.

In accordance with the present invention, the floating storage tank 20is connected to the satellite station 16 by a fluid transportation path,as shown in FIGURES 1 and 1A, to comprise a rigid transportation pipe326 depending to a point just above the marine bottom 12 and terminatingin a funnel 328, and a flexible line 330 extending from the funnel 328to the pumping section 334 (illustrated schematically in FIGURE 1A) inthe satellite station 16. A short section 336 of the flexible line 330,at the end of the line connected to the rigid transportation pipe 326within the funnel, is of a weaker material or of the same material asthe rest of the line 330, but has a thinner wall. By this arrangement,if the floating storage tank 20 should break its moorings and floataway, the interconnecting fluid transportation path would tend torupture, at its weakest point, the short section 336, in the flexibleline 330 within the funnel 328. This would permit most of the fluidproducts to be saved and only the small amount in the flexible line 328at the time to be lost. The fluid products in the rigid pipe 326 at thetime of the rupture would be driven up into the storage tank 20 by thehydrostatic pressure. A pressure actuated switch 338 is included in theflexible line 330 to open the electrical circuit supplying power to apump 340' in the pumping section 334 in satellite station 16 if theflexible line 328 were to rupture. Such a switch would be actuatedbyabnormally high or low pressure, depending on the water depth and thepump outlet pressure. It is also advisable to mount a pressurecontrolled valve 342 in the outer end of the flexible line 330, justbelow the designed rupture portion to retain the fluid products in theflexible line 328 subsequent to any rupture. Furthermore, the storagetank 20 is moored as far to the side of the subsea field as possible(FIGURE 1) so that if it should break loose, its mooring lines 332,extending to the marine bottom 12, would not snag in the subseaequipment.

Although the present invention has been described in connection withdetails of the specific embodiments thereof, it is to be understood thatsuch details are not intended to limit the scope of the invention. Eachof the described units of the subsea system previously discussed couldconceivably be utilized without each and every one of the other units.For example, the satellite station 14 could be used without theparticular robot wireline unit 182 or the robot welder 52. The terms andexpressions employed are intended to be used in a descriptive sense onlyand there is no intention of excluding such equivalents in the inventiondescribed as fall within the scope of the claims. Now having describedthe subsea system herein disclosed, reference should be had to theclaims which follow.

What is claimed is:

1. A fluid transportation path for conveying fluids upward through abody of Water, comprising: a rigid fluid transportation pipe adapted tobe substantially vertically located in a body of water, said rigidtransportation pipe adapted to terminate at a first end thereof, abovethe surface of the body of water, said rigid transportation pipe adaptedto terminate at a second end thereof, far beneath the surface of a bodyof water, in an inverted funnel, conduit means adapted to direct fluidinto said second end of said rigid transportation pipe from a source offluid, far beneath the surface of a body of water, a section of saidconduit means within said inverted funnel being the weakest point insaid fluid transportation path Whereby, if a rupture should occur insaid fluid transportation path, it would occur within said funnel and aminimum amount of produced fluid would be lost into the surrounding bodyof water.

2. A fluid transportation path for conveying fluids upward through abody of water as recited in claim 1 wherein said conduit means adaptedto direct fluid into said second end of said rigid transportation pipefrom a source of fluid beneath the surface of a body of Water is aflexible transportation line connected to said rigid transportation pipewithin said inverted funnel.

3. A fluid transportation path for conveying fluids upward through abody of water as recited in claim 2 wherein said rigid transportationpipe terminates at the first end thereof in a fluid storage tank adaptedto float at the surface of a body of water.

4. A fluid transportation path for conveying fluids upward through abody of water as recited in claim 3 wherein there are means for mooringa tanker to said storage tank and means for offloading stored fluidsfrom said storage tank into said tanker.

5. A subsea system for the production of fluid minerals from subaqueousdeposits through wells having wellheads located beneath the surface of abody of water, comprising: .a, plurality of underwater wellhead units,each of said wellheads of said wellhead units being equipped with atleast one remotely actuatable valve for controlling the flow of producedfluid from the respective well; at least one production satellitestation located beneath the surface of said body of water; flowlinessupported over at least a portion of their lengths on said marinebottom, connecting each of said plurality of underwater wellheads,through the respective remotely actuatable wellhead valve, with theinterior of said satellite station; means Within said satellite stationfor combining the produced fluid from all of said wells flowing throughsaid flowlines and directing said produced fluid through a main outletline; means within said satellite station for selectively testing saidproduced fluid flowing through each of said flowlines individually;means for actuating said remotely actuatable wellhead valves in responseto the results of the selective testing of the produced fluid flowingthrough said flowlines to optimize production; and fluid pump meansconnected between said main outlet line, a fluid transportation pathextending to a storage tank on the surface of the body of water forstoring the fluid minerals produced in said subsea system; said fluidtransportation path having a rigid fluid transportation pipe dependingsubstantially vertically from said storage tank and terminating justabove said marine bottom in an inverted funnel and a flexibletransportation line extending between said funnel and the outlet of saidpump means; and a section of said flexible transportation line, withinsaid funnel, being the weakest point insaid fluid transportation pathwhereby, if a rupture should occur in said fluid transportation path, itwould occur within said funnel and a minimum amount of produced fluidwould be lost into the surrounding body of Water.

6. In the subsea production system of claim 5, pressure actuated switchmeans for shutting off said pump means in response to abnormal pressuresin said fluid transportation path indicating a rupture in said fluidtransportation path.

References Cited UNITED STATES PATENTS 2,783,970 3/ 1957 Gillespie --8 X3,292,695 12/1966 Haeber 166.5 3,366,173 1/1968 McIntosh 166.5

CHARLES E. OCONNELL, Primary Examiner.

RICHARD E. FAVREAU, Assistant Examiner.

